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MA: Fachverband Magnetismus

MA 28: Magnetic Materials I

MA 28.9: Vortrag

Mittwoch, 2. April 2014, 17:15–17:30, HSZ 04

X-ray absorption magnetic circular dichroism study on ferromagnetic SrRuO₃ — •Stefano Agrestini¹, Zhiwei Hu¹, Nils Hollmann¹, Chang-Yang Kuo¹, Qiang Liu¹, Eric Pellegrin², Pierluigi Gargiani², Philipp Gegenwart³, Melanie Schneider³, Sebastian Esser³, Alexander Komarek¹, and Liu Hao Tjeng¹ — ¹Max Planck Institut CPfS, Dresden, Germany — ²CELLS-ALBA, Barcelona, Spain — ³I. Physikalisches Institut, Georg-August-Universität, Göttingen, Germany

SrRuO₃ have received intensive research interest because it is one of the very few ferromagnetic metallic 4d transition metal oxides, with a high Curie temperature of T_c=160 K, as well as unusual negative spin polarization and magnetoresistive properties. Ru⁴⁺ has S=1 spin state, however, very recently it has been suggested that a high spin state (S=2) of Ru⁴⁺ could be stabilized on compressively in-plane strained SrRuO₃ films.

Here we report a study of x-ray magnetic circular dichroism (XMCD) in x-ray absorption (XAS) on the Ru-L2,3 edge on SrRuO₃ thin films with different substrate orientations, the (111) and (001) surfaces of SrTiO₃. Only a very small directional dependence was found. The XMCD spectra of a SrRuO₃ single crystal has been recorded and shows good agreement with the spectral line shape of the thin films. We could not find evidence of the stabilization of a high spin S=2 state. Applying the XMCD sum rules, it can be seen that the orbital momentum of the Ru ions is almost quenched. This surprising finding could be explained by an itinerant character of the Ru electrons.